With the development of application of the Internet of Things, the number of used Internet of Things devices increases constantly and rapidly. As an important connection link for bearing data communication between the Internet of Things devices, a communications network bears a constantly increasing amount of data and a constantly increasing number of service types.
During the development process of the Internet of Things, to decrease a cost of Internet of Things terminals to accelerate popularization of the Internet of Things, an operator proposes a concept of a low cost terminal in a long term evolution (LTE) conference of the third generation partnership project (3GPP).
A low cost terminal only supports small bandwidth, such as 1.4 M, and therefore may also be called a narrowband user terminal. The low cost terminal can largely save a cost of an Internet of things terminal. For most Internet of things devices, small bandwidth can meet their needs of data transmission. Therefore, an Internet of things terminal, as a low cost terminal, can largely decrease a device cost without affecting communication, and it can be further predicted that the low cost terminal has a bright prospect in the Internet of things.
In the prior art, there is a technical solution that a position of a new downlink narrowband control channel domain is notified by using a physical broadcast channel (PBCH) for a low cost terminal to use, so that the low cost terminal only occupies a part of a frequency band of a broadband when performing broadband access, so as to save bandwidth and reduce receiving and processing complexity.
However, the inventor finds in researches that although many Internet of Things services only require a low transmission rate, control information of the services has a high priority. Particularly, sending and receiving conditions of downlink control information may directly affect system performance. Physical resource blocks (PRB) in a narrowband system in the prior art have a small frequency interval and high relevance, and may be in deep fading at the same time. As a result, control information transmitted in the narrowbands cannot be accurately received or sent by some terminals in deep fading. Therefore, the prior art at least has a defect. In that a control channel of a low cost terminal has poor reliability of control information transmission, thereby affecting system performance.